JP2001122131A - Coupling structure for telescopic shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure a stroke amount of a collapse during collision and to reduce manufacturing costs while positively preventing an occurrence of a backlash. SOLUTION: An inner shaft 4, an intermediate pipe member 5, and an outer shaft 6 are each formed with non-circular cross sections and they are mutually fitted together. Long grooves 7, 8, and 9 extending in an axial direction are each formed on the inner shaft 4, the intermediate pipe member 5, and the outer shaft 6. A plate spring member 10 is interposed in a fitting part of the inner shaft 4 and the intermediate pipe member 5, and a plate spring member 11 is interposed in a fitting part of the intermediate pipe member 5 and the outer shaft 6. Both end parts 10b, 10c, 11b and 11c of the plate spring members 10 and 11 are engaged in each groove 7, 8, and 9 of the inner shaft 4, the intermediate pipe member 5, and the outer shaft 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure of a telescopic shaft used in a steering device of an automobile and the like. The present invention relates to a joint structure of a telescopic shaft that reliably reduces the manufacturing cost while reducing manufacturing costs.

[0002]

2. Description of the Related Art In a steering apparatus of an automobile,
In the event of a vehicle collision or the like, a part of the steering shaft is collapsed and contracted to protect the driver. Specifically, the inner shaft on the front side of the steering shaft and the outer shaft on the rear side of the steering shaft are spline-fitted or serrated-fitted, so that at the time of a collision or the like, the fitting portion between the two is collapsed. Thus, the inner shaft is housed in the outer shaft, and the steering shaft is contracted.

In such a two-stage fitting structure in which the inner shaft and the outer shaft are spline-fitted,
U.S. Pat. No. 5,464,251 because it is not possible to secure a sufficient stroke amount during collapse.
No. 5,685,565, an intermediate pipe member is interposed between an inner shaft and an outer shaft, and each is fitted to form a three-stage fitting structure. In this case, a sufficient stroke amount of the collapse in a collision or the like is ensured.

Specifically, US Pat. No. 5,464,25
In FIG. 6, the intermediate pipe member is spline-fitted to the inner shaft, and the outer shaft is spline-fitted to the intermediate pipe member.
It has a stepped fitting structure. Also, the inner shaft and the intermediate pipe member are configured to be slidable in the axial direction while applying a predetermined frictional force, while one projection is formed on the inner peripheral surface of the outer shaft, The outer shaft and the outer shaft are press-fitted to each other by a single protrusion so that the outer shaft cannot slide in the axial direction.

Accordingly, when the steering shaft is assembled, the intermediate pipe member is slid in the axial direction with respect to the inner shaft to adjust the length of the steering shaft. The press-fitting portion formed by the protrusion of the shaft is collapsed, and the inner shaft, the intermediate pipe member, and the outer shaft overlap with each other to contract the steering shaft. As described above, the three-stage fitting structure allows a sufficient stroke amount at the time of collapse.

In US Pat. No. 5,685,565, an intermediate pipe member is fitted to an inner shaft, and an outer shaft is fitted to the intermediate pipe member. I have to. Further, the inner shaft, the intermediate pipe member, and the outer shaft are formed in a non-circular cross section so that they cannot rotate with each other. Furthermore, a resin injection portion is provided at each of the fitting portion between the inner shaft and the intermediate pipe member, and the fitting portion between the intermediate pipe member and the outer shaft, and these are configured so as not to slide in the axial direction with each other. I have. Thus, at the time of collision or the like, the injection location of the resin is collapsed, and the inner shaft, the intermediate pipe member, and the outer shaft overlap with each other, and the steering shaft is contracted. As described above, the three-stage fitting structure allows a sufficient stroke amount at the time of collapse.

[0007]

In the joint structure of the telescopic steering shaft described above, in the above-mentioned U.S. Pat. No. 5,464,251, one projection is formed on the inner peripheral surface of the outer shaft. The pipe member and the outer shaft are press-fitted by the one projection so as not to slide in the axial direction. However, since the press-fitting portion is only one portion, when the bending load is applied to the steering shaft, the outer shaft slightly swings about the one press-fitting portion with respect to the intermediate pipe member due to the bending load. (Hereinafter referred to as “torsion”), and as a result, “play” may occur between the intermediate pipe member and the outer shaft.

Further, the above-mentioned US Pat. No. 5,685,565
In the gazette, a fitting portion between the inner shaft and the intermediate pipe member, and a fitting portion between the intermediate pipe member and the outer shaft are provided with injection portions of resin, respectively,
These are configured so that they cannot slide with respect to each other in the axial direction. However, this resin injection may cause an increase in the number of steps and, consequently, a rise in manufacturing costs. In addition, since the resin injection portion may be inferior in heat resistance, there is a demand that the resin injection should not be used as much as possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and has been developed while ensuring a sufficient stroke amount of a collapse at the time of a collision and the like while reliably preventing the occurrence of "play". It is an object of the present invention to provide a joint structure of a telescopic shaft that reduces costs.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, a connecting structure of a telescopic shaft according to the present invention is a non-circular connecting structure of a shaft which is axially expandable and non-rotatable. An outer shaft formed in a non-circular cross section corresponding to the non-circular cross section of the inner shaft is fitted non-rotatably and slidably in the axial direction on the inner shaft formed in the cross section, and is fitted to the inner shaft and the outer shaft. Respectively, forming a long groove extending in the axial direction, a fitting portion between the inner shaft and the outer shaft, a leaf spring member is interposed, and an end of the leaf spring member is attached to the inner shaft and the inner shaft. It is characterized in that it engages with each long groove with the outer shaft.

As described above, according to the present invention, the inner shaft and the outer shaft are formed to have a non-circular cross-section so that they cannot rotate. Therefore, it is necessary to form splines and the like as in the prior art. Therefore, the manufacturing cost can be reduced.

Further, since a leaf spring member is interposed at a fitting portion between the inner shaft and the outer shaft, "play" generated between both shafts is reliably prevented by the urging force of the leaf spring member. can do.

Further, since the ends of the leaf spring member are engaged with the respective long grooves of the inner shaft and the outer shaft, it is possible to prevent the shaft from coming off.

Further, by changing the biasing force and shape of the leaf spring member interposed in the fitting portion between the inner shaft and the outer shaft, the sliding load of the outer shaft with respect to the inner shout can be adjusted.
It is also possible to adjust the "play" (torsion rigidity) in the rotation direction of the steering shaft.

Further, unlike the prior art, since no resin injection is used, the manufacturing cost can be reduced and the heat resistance is excellent.

Further, an intermediate pipe member may be interposed between the inner shaft and the outer shaft, and each may be fitted to form a three-stage fitting structure. In this case,
A sufficient stroke amount of the collapse at the time of a collision or the like can be secured.

In the present invention, from the viewpoint of ensuring a sufficient stroke amount during collapse, an intermediate pipe member is interposed between the inner shaft and the outer shaft.
It is preferable to use a step-type fitting structure. However, when a large stroke amount is not required at the time of collapse, a two-step type fitting that does not use an intermediate pipe member is provided as described in claim 1. A structure may be used.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing a connecting structure of a telescopic shaft according to an embodiment of the present invention.

FIG. 1A is a longitudinal sectional view of a vehicle steering shaft to which a connecting structure of a telescopic shaft according to a first embodiment of the present invention is applied, and FIG. 1B is a longitudinal sectional view of FIG. It is a cross-sectional view along the bb line of a). FIG.
FIG. 2 is a longitudinal sectional view showing a state where the vehicle steering shaft shown in FIG. 1 is contracted.

As shown in FIG. 1, a lower universal joint 1 and an upper universal joint 2 of a steering shaft for a vehicle are provided, and an intermediate shaft 3 is provided therebetween. This intermediate shaft 3 is connected to an inner shaft 4 connected to the lower universal joint 1, an intermediate pipe member 5 fitted to the inner shaft 4, and fitted to the intermediate pipe member 5 and to the upper universal joint 2. And a combined outer shaft 6.

The inner shaft 4, the intermediate pipe member 5,
The outer shaft 6 and the outer shaft 6 are each formed in a triangular shape having a non-circular cross section. Because of the non-circular cross-section, it is configured to be non-rotatable, so that there is no need to form a spline or the like as in the related art, and the manufacturing cost can be reduced.

The inner shaft 4, the intermediate pipe member 5,
The outer shaft 6 has long grooves 7, 8, 9 extending in the axial direction, respectively.

A leaf spring member 10 is interposed at a fitting portion between the inner shaft 4 and the intermediate pipe member 5.
A leaf spring member 11 is interposed at a fitting portion between the intermediate pipe member 5 and the outer shaft 6.

A plurality of projections 10a, 11a are formed on the leaf spring members 10, 11 respectively, and the inner shaft 4 and the intermediate pipe member 5 are fitted by the urging force of the projections 10a. The joint portion is elastically pressed to reliably prevent "play" between the two, and the urging force of the projection 11a elastically causes the fitting portion between the intermediate pipe member 5 and the outer shaft 6 to elastically. Pressing is surely preventing "play" between them.

Both ends 1 of these leaf spring members 10 and 11
Ob, 10c, 11b, and 11c are caulked substantially perpendicularly, and are engaged with the long grooves 7, 8, and 9 of the inner shaft 4, the intermediate pipe member 5, and the outer shaft 6, respectively. This prevents the shaft from coming off.

With such a configuration, when the steering shaft is assembled, the inner shout 4 is changed by changing the urging force and the shape of the leaf spring members 10 and 11.
And the sliding load of the outer shaft 6 on the intermediate pipe member 5 can be adjusted, and the "play" (torsional rigidity) in the rotational direction of the steering shaft can also be adjusted. .

At the time of a collision or the like, as shown in FIG.
The inner shaft 4, the intermediate pipe member 5, and the outer shaft 6 resist the urging force of the leaf spring members 10, 11.
Shrink so as to overlap each other. in this way,
Because of the three-stage fitting structure, a sufficient stroke amount during collapse can be secured.

Next, FIG. 3A is a longitudinal sectional view of a vehicle steering shaft to which a telescopic shaft coupling structure according to a second embodiment of the present invention is applied, and FIG.
FIG. 4 is a cross-sectional view taken along line bb in FIG. FIG. 4 is a longitudinal sectional view showing a state where the vehicle steering shaft shown in FIG. 3 is contracted. FIG. 5 is a sectional view of a main part of the lower-side universal joint. FIG. 6 is a sectional view of a main part of the upper-side universal joint.

In the second embodiment, the inner shaft 4, the intermediate pipe member 5, and the outer shaft 6
Each has a non-circular hexagonal cross section. Also in this case, since the rotation is not possible due to the non-circular cross section, there is no need to form a spline or the like, and the manufacturing cost can be suppressed.

The inner shaft 4, the intermediate pipe member 5, and the outer shaft 6 have respective long grooves 7,
End faces 8 and 9 on the vehicle front side are formed as slopes, and end parts 10b and 10b of the leaf spring members 10 and 11 on the vehicle front side.
11b is formed in an arc shape, and the leaf spring members 10, 1
End portions 10c and 11c on the rear side of the vehicle 1 are folded back so as to correspond to slopes of the long grooves 8 and 9.

As a result, as shown in FIG. 4, during the collapse, the arc-shaped ends 10b, 11b of the leaf spring members 10, 11 on the vehicle front side slide on the slopes of the long grooves 7, 8, so that the long grooves 7, 8 does not get caught on the end face.

When assembling the intermediate shaft 3, arcuate ends 10b, 10b,
11b does not need to be swaged in an arc shape after the inner shaft 4, the intermediate pipe member 5, and the outer shaft 6 are fitted to each other. That is, when the inner shaft 4 is fitted to the intermediate pipe member 5, the leaf spring member 10 is placed inside the intermediate pipe member 5. This is because the end portion 10b can elastically ride on the inner shaft 4 as shown by a virtual line in FIG. The arc-shaped end portion 11b of the leaf spring member 11 also acts similarly when the intermediate pipe member 5 is fitted to the outer shaft 6.

Further, other configurations and operations in the second embodiment are the same as those in the first embodiment.

As shown in FIG. 5, the outer peripheral surface of the end 4a of the inner shaft 4 is cut into a round shape so as to fit into the round hole 1a of the yoke of the lower universal joint 1. is there. As shown in FIG. 6, the outer peripheral surface of the end 2 a of the yoke of the upper side universal joint 2 is
It is formed in a round shape so that it can be fitted to the inner peripheral surface of the hexagonal end 6a.

The present invention is not limited to the above-described embodiment, but can be variously modified. For example, as described above, the present invention uses a three-stage fitting structure in which an intermediate pipe member is interposed between an inner shaft and an outer shaft from the viewpoint of ensuring a sufficient stroke amount during collapse. However, when a large stroke amount is not required at the time of collapse, a two-stage fitting structure that does not use an intermediate pipe member may be used.

[0036]

As described above, according to the present invention,
Since the inner shaft and the outer shaft are formed to have a non-circular cross-section so as to be non-rotatable, there is no need to form splines or the like as in the related art, and the manufacturing cost can be reduced.

Further, since a leaf spring member is interposed at the fitting portion between the inner shaft and the outer shaft, "play" generated between both shafts is reliably prevented by the urging force of the leaf spring member. can do.

Further, since the ends of the leaf spring member are engaged with the respective long grooves of the inner shaft and the outer shaft, it is possible to prevent the shaft from "falling out".

Further, by changing the biasing force and the shape of the leaf spring member interposed in the fitting portion between the inner shaft and the outer shaft, the sliding load of the outer shaft with respect to the inner shout can be adjusted.
It is also possible to adjust the "play" (torsion rigidity) in the rotation direction of the steering shaft.

Furthermore, unlike the prior art, no resin injection is used, so that the manufacturing cost can be reduced and the heat resistance is excellent.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of a vehicle steering shaft to which a coupling structure of a telescopic shaft according to a first embodiment of the present invention is applied, and FIG. b
Cross-sectional view along the line.

FIG. 2 is a longitudinal sectional view showing a state in which the vehicle steering shaft shown in FIG. 1 is contracted.

FIG. 3A is a longitudinal sectional view of a vehicle steering shaft to which a joint structure of a telescopic shaft according to a second embodiment of the present invention is applied, and FIG. b
Cross-sectional view along the line.

FIG. 4 is a longitudinal sectional view showing a state where the vehicle steering shaft shown in FIG. 3 is contracted.

FIG. 5 is a sectional view of a main part of a lower-side universal joint.

FIG. 6 is a sectional view of a main part of an upper-side universal joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower side universal joint 2 Upper side universal joint 3 Intermediate shaft 4 Inner shaft 5 Intermediate pipe member 6 Outer shaft 7, 8, 9 Long groove 10, 11 Leaf spring member 10a, 11a Projection part of leaf spring member 10b, 10c, 11b, 11c End of leaf spring member

Claims (2)

[Claims] 1. A coupling structure of a shaft which is axially expandable and contractible and non-rotatably coupled, wherein said inner shaft has a non-circular cross section corresponding to the non-circular cross section of said inner shaft. The outer shaft is fitted non-rotatably and slidably in the axial direction, and is fitted to the inner shaft and the outer shaft.
In each case, a long groove extending in the axial direction is formed, a leaf spring member is interposed at a fitting portion between the inner shaft and the outer shaft, and an end of the leaf spring member is
A coupling structure for a telescopic shaft, wherein the coupling structure is engaged with respective long grooves of the inner shaft and the outer shaft. 2. An intermediate pipe member having a non-circular cross section corresponding to the non-circular cross section is fitted between the inner shaft and the outer shaft so as to be non-rotatable and slidable in the axial direction. A long groove extending in the axial direction is formed in the intermediate pipe member, and a leaf spring member is interposed in a fitting portion between the inner shaft and the intermediate pipe member, and the intermediate pipe member, the outer shaft, A leaf spring member is interposed in the fitting portion of (a), and ends of these leaf spring members are engaged with respective long grooves of the inner shaft, the intermediate pipe member, and the outer shaft. Item 2. A coupling structure of a telescopic shaft according to Item 1.